The present invention generally relates to spark plugs for igniting the fuel charge in an internal combustion engine, and is particularly concerned with an improved spark plug construction which improves combustion pressure, fuel mileage and diminishes exhaust pollution as compared with known prior art plugs.
Prior art spark plugs are well known. Such spark plugs typically include a center electrode and a ground electrode spaced apart from the center electrode. When a sufficient electrical potential is provided across the gap, a spark jumps across the gap. This spark can be used to ignite an air-fuel mixture within an internal combustion engine.
U.S. Pat. No. 5,051,651 (xe2x80x9cthe ""651 patentxe2x80x9d) details a xe2x80x9ccylindrical holexe2x80x9d that is created around the center electrode by shielding of the outer ground electrode. The ""651 patent asserts that xe2x80x9cignition seedsxe2x80x9d multiply inside of this cylindrical hole. The ground electrode, in all examples, has a xe2x80x9csubstantially concave inner surface complimenting the redial face of said center electrodexe2x80x9d (Column 8, line 33). This creates a concentric curved surface that has an inner radius equal to xe2x80x9cthe sum of the radius of the center electrode and a spark gap can be nearly equal to the radius of the cylindrical holexe2x80x9d (Column 1, line 54).
As seen in FIG. 13 of the ""651 patent, and in the language in independent Claim 18, the invention relies specifically on spark strike areas wherein xe2x80x9cat least a portion of each said inner orthogonal sides is provided with a concave surface having a curvature complimenting the axial face of the center electrodexe2x80x9d.
Since all sparks travel along the shortest path, center electrode to ground electrode, the effective surfaces of the ""651 patent are similar to other concentric ring designs (U.S. Pat. Nos. 1,748,338; 1,942,242; 1,912,516; 5,430,346; 5,280,214) where the ground electrode is shaped in a complimenting radius centered on the same axis as the center electrode. The ""651 patent, at the functional core where the spark actually jumps, performs similarly to other concentric ring designs.
However, it is believed by the applicant that concentric ring designs have shown no performance benefit over standard spark plug designs.
Reference is also made to U.S. Pat. No. 5,612,586, in which particular importance is placed upon eliminating the 90 degree bend common to a standard spark plug.
The above prior art patents include some advantageous features. However, there is always a need for an improved plug design which provides improved fuel efficiency and reduced emissions.
The present invention relates to the use of a spark plug providing edge corners in a tangential relationship with the central electrode.
Therefore it is an object of the present invention to provide an improved spark plug.
It is a further object of the present invention to provide an improved spark plug ground electrode.
It is a further object of the present invention to provide an improved spark plug which exhibits improved fuel efficiency.
It is a further object of the present invention to provide an improved spark plug which exhibits improved combustion pressure.
It is a further object of the present invention to provide an improved spark lug which provides decreased pollution.
Other objects, feature, and advantages of the present invention will become apparent upon reading the following detailed description of the preferred embodiment of the invention when taken in conjunction with the drawings and the appended claims.